Insert molding, as referred to herein, generally refers to the practice of molding a material about or around a separate piece, so that the molded material is integral with, bonded to, or partially or completely surrounds or encapsulates the separate insert piece in a finished part. To accomplish this, the insert piece must be inserted into the cavity of a mold, such as a plastic injection mold or casting mold, prior to injecting the mold with a molding material. A new insert piece must be inserted into the mold at the start of each mold cycle. Typically, the insert is positioned in the mold by hand or by robot, during the period when the mold is opened between injection/compression cycles. Of course, this additional operation per part greatly reduces the rate of mass production.
In continuous production of insert molded parts, the insert pieces must be arranged for rapid and continuous insertion into a mold. Small insert pieces may be arranged upon racks, or stacked in a magazine which feeds into the mold cavity. The insert piece supply system be constantly re-stocked and monitored throughout the production process. Typically, the insert pieces are manufactured in an operation completely separate from the molding operation, and then arranged for continuous insert molding production. This amounts to two different manufacturing operations in order to produce a single finished part.